Coverity CIDs 578 and 579
In source file lib/softoken/pk11db.c, there are numerous places where we
find loops containing one or more invocations of the SECMOD_HANDLE_STRING_ARG
macro. That macro checks for a string match, then allocates memory for a copy
of a string, and stores the allocated memory address in a target pointer.
If the same macro invocation should occur twice in the loop, e.g. because the
sought string occurred more than once in the source string, all but the last
allocation of the corresponding value string would be leaked.
Coverity reports 11 occurrences of this in all, one for each macro invocation.
The most straightforward solution is to have that macro free the contents of
the target pointer, if it is not already NULL. patch forthcoming.

Created attachment 223507[details][diff][review]
patch v1, part 2
OOps, that patch had two parts, and I previously only attached one of them.
So please review this part, also, as if the two parts are being reviewed
together.